I need to hide cancel button while file upload is in progress as dispalyed in the image below.

Hi,

Please set the cancel button to another button, then you can hide the custom cancel button to achieve this requirement, like below.

   <CuteWebUI:UploadAttachments ID="uploader1" runat="server" CancelButtonID="btn_Cancel">
        </CuteWebUI:UploadAttachments>
        <asp:Button ID="btn_Cancel" runat="server" Style="visibility: hidden" />
 

Regards,

Ken